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Shrinkage rate control during a flash state by current‐ramping for 3 mol% Y 2 O 3 ‐doped ZrO 2 polycrystals
Author(s) -
Ishino Yuki,
Taguchi Kimihiro,
Koike Masao,
Tokunaga Tomoharu,
Yamamoto Takahisa
Publication year - 2021
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.17912
Subject(s) - shrinkage , materials science , current density , doping , analytical chemistry (journal) , grain size , composite material , indentation , current (fluid) , vickers hardness test , flash (photography) , metallurgy , electrical engineering , microstructure , optics , chemistry , optoelectronics , physics , chromatography , quantum mechanics , engineering
Abstract 3 mol% Y 2 O 3 ‐doped ZrO 2 green compacts with rectangular shapes were sintered by maintaining the shrinkage rates at constant values under alternating electric fields by ramping the electric current during flash states. Green compacts were furnace‐heated under 40‐100 V rms /cm until current hits an initial current limit of 100 mA rms . After then, current‐ramping was started to keep the shrinkage rates constant by increasing the limit current value using a programmable power supply operating in a current control mode. Highly densified 3 mol% Y 2 O 3 ‐doped ZrO 2 polycrystals with a density of 6.05 g/cm 3 as a bulk density and a grain size of about 0.4 μm were obtained at a furnace temperature of about 930℃, 50 V rms /cm with 1000 Hz and shrinkage rate of about 120 μm/min (0.8%/min against initial lengths of green compacts). The Vickers hardness and indentation fracture toughness of the compact exhibit similar values to those obtained from thermally sintered compacts.